Low power consumption is necessary for a processor used in a portable information terminal. An example of lowering the power consumption of the processor includes a method for replacing nonvolatile memories with cache memories using a static random access memory (SRAM) with large standby energy.
Examples of the nonvolatile memories include a magnetoresistive random access memory (MRAM), a ferroelectric random access memory (FeRAM), a resistance random access memory (ReRAM), and the like. Among the nonvolatile memories which have been proposed, especially, the MRAM may simultaneously satisfy the following three characteristics. That is, high rewriting resistance, operation performance capable of high-speed readout and writing, and a cell size capable of high integration.
However, the MRAM is high in a bit error rate, compared to the SRAM or DRAM.